In a comment on yesterday’s post about words ending in xión and cción, Susan asked me to explain the difference between x and j, especially as regards the case of Quixote vs. Quijote.

My trusty copy of the Real Academia’s Ortografía provided an instant answer. A short section of the book (6.2.2.3.2) addresses the topic. Here’s a rough translation/condensation:

Until the beginning of the 19th century, the sound of j or g (before e/i) could also be represented with x. So, it was normal to see spellings like embaxador, exemplo, mexilla, etc. that are written with a j today. In 1815, the Real Academia decided to eliminate this use of x…Nevertheless, some traces remain of the former use of x in certain place names like México, Oaxaca, or Texas, and people-names (“antropónimas”) like the first name Ximena and last names Ximénez or Mexía…In the case of ‘México’ and its derived forms, spellings with j were common until recently in Spain, where… the x spellings have since prevailed because they’re the ones used in their own country and, for the most part, in the rest of Latin America.

In the case of Quijote/Quixote, the “official” spelling is j. The version with x is old-fashioned, and was used notably in the first edition, pictured above.